The alcoholic beverage industry in the US has a market of $200 Billion, of the $350 Billion market of the total beverage industry. Almost half of the alcoholic beverages, except malt beverages like beer, are aged in wooden barrels to impart distinct taste and flavor by allowing the chemical components in alcoholic beverages to react and create distinctive aroma and palate. Aging also involves the reaction of the components of the fermented liquids over time. These beverages include whiskey, wine, bourbon, rum, tequila, cognac and many more. The aging process can range from a few months to decades before the beverage is ready to drink. This length of time is needed to allow sufficient leaching of chemicals like phenols from the wood barrels wherein the beverage is stored. In ideal situations, the aging is allowed to proceed slowly as vibrations, and heat fluctuations can hasten taste deterioration and cause an adverse effect on the beverage. In general, a beverage has a greater potential to develop complexity and more aromatic bouquet if it is allowed to age slowly in a relatively cool environment. However, the current methodology of aging produces significant variability due to concentration gradients within the wooden barrel since the contact with wood is limited to liquids in contact only.
There is a long history of man using artificial means to try to accelerate the natural aging process. In Ancient Rome, a smoke chamber known as a fumarium was used to enhance the flavor of the wine through artificial aging. Amphorae were placed in the chamber, which was built on top of a heated hearth, in order to impart a smoky flavor to the wine that also seemed to sharpen the acidity. The wine would sometimes come out of the fumarium with a paler color just like aged wine. Modern winemaking techniques like micro-oxygenation can have the side effect of artificially aging the wine. In the production of Madeira and Rancio wines, the wines are deliberately exposed to excessive temperatures to accelerate the maturation of the wine. The current method of aging alcoholic beverages does not allow adjusting the temperature of the beverage to finer limits, nor does it allow cycling of temperature ranges during aging. It is highly likely that an alcoholic beverage maker may develop may develop a temperature cycling that will provide an optimal flavor.
Generally, an alcoholic beverage in a holding vessel equipped with the automatic temperature control system will significantly enhance the quality and consistency of flavor achieved. It is noteworthy that all reactions, including leaching and chemical reactions that take place within the alcoholic beverage over time release energy if they are instantaneous in the form of heat causing localized variability of temperature that can have significant impact on the nature of reaction.
Other techniques used to age wine artificially (with inconclusive results on their effectiveness) include shaking the wine, exposing it to radiation, magnetism or ultra-sonic waves. More recently, experiments with artificial aging through high-voltage electricity have produced results above the remaining techniques, as assessed by a panel of wine tasters.
The general consensus is that shaking or mixing alcoholic beverages while aging adversely affects their quality; aging in wooden barrels often requires rotating barrels, even though it is kept to a minimum. There is an unmet need to create a system of mixing of alcoholic beverages during aging that does not involve any external force. There is a need to invoke the thermodynamic principles of mixing such as creating an environment wherein the concentration of extracted chemicals is different, forcing the browning motion to cause mixing of liquids.
It is also important to understand that any shaking of the liquid may also impart energy that may result in reactions that might not happen when the liquid is left undisturbed. The current method of aging alcoholic beverages ignores this aspect. There is a need to develop an apparatus that will allow extreme gentle mixing, the best being what is caused by a diffusion process. To achieve this, in a larger vessel, the contact between wood and the beverage must be provided at a micro level, eliminating variability in the concentration gradient, regardless of the size of vessel or the volume of beverage aged in a single vessel.
Although oak barrels have long been used by winemakers, many wineries now use oak wood chips for aging wine more quickly and also adding desired woody aromas along with butter and vanilla flavors. Oak chips can be added during fermentation or during aging. In the latter case, they are generally placed into fabric sacks and placed into the aging wine.
The diversity of chips available give winemakers numerous options. Oak chips have the benefit of imparting intense oak flavoring in a matter of weeks while traditional oak barrels would need a year or more to convey similar intensity. The critics claim that the oak flavoring from chips tend to be one-dimensional and skewed towards the vanilla extract with the wines still lacking some of the physical benefits that barrel oak imparts. The use of oak powder is also less common than chips. Wines made from these barrel alternatives typically do not age as well as wines that are matured in barrels mainly due to unpredicted transfer rates. In a wine barrel, a flat surface causes movement of components in the wood, therefore, any extrapolation of the surface area calculations must maintain the surface integrity. Prior to 2006, the practice of using oak chips was outlawed in the European Union.
Improvements in micro-oxygenation have allowed winemakers to mimic better the gentle aeration of oak barrels in stainless steel tanks with oak chips.
The use of oak chips in wine making needs to be examined to ascertain why this approach is not conducive to aging of alcoholic beverages. First, it is the consideration of the surface area provided for partitioning of chemicals out of wood and into the alcoholic beverage. It is difficult to project the changes in surface area and thus make conclusions about what is appropriate; secondly, the wood chips may not have been treated the same way it is possible to treat a wooden barrel, including charring, aging and other attributes generally imparted to the wooden barrel prior to its use. An ideal situation would be if the partitioning of chemicals from the wood is allowed to go through a linear surface mimicking the wooden barrel; the Fick's law of diffusion is agnostic to how the surface was created. There is a need to create a method of increasing the surface area exposed to the extraction of chemicals from wood keeping the geometry same and proportional. One way to do this would be to increase the total linear flat surface area exposed.
While the traditional aging of alcoholic beverages in wooden barrels has worked for a very long time, perhaps centuries, there is a need to bring a major change to the science and the art of aging alcoholic beverages. It is necessary because of a variety of difficulties and disadvantages in the traditional methods. However, any change in the traditional process must allow for replicating the process that has been developed over centuries.
The porous nature of an oak barrel allows some levels of evaporation and oxygenation to occur in wine but typically not at levels that would cause oxidation or spoilage of the wine. In a year, the typical 59-gallon barrel can lose anywhere from 5½ to 6½ gallons of wine through the course of evaporation. This evaporation (of mostly alcohol and water) allows the wine to concentrate its flavor and aroma compounds. Small amounts of oxygen are allowed to pass through the barrel and acts as a softening agent upon the tannins of the wine. The traditional method of aging alcoholic beverages in wood barrels has little control over aeration or oxygenation of the alcoholic beverage and it is highly dependent on the porosity of the wood, which might change from barrel to barrel and from one type of wood to another, how it is aged, how it is cut and shaved and how is the barrel put together.
There is a need to eliminate this variability to provide a more consistent exposure to air or oxygen and, where necessary, block exposure to oxygen by flushing the surface with an inert gas such as argon or nitrogen. This cannot be achieved in using wooden barrels; however, a holding vessel with a port to allow entry and to exhaust of gases will make this process more reliable and provide reproducible results.
Wine barrels, especially those made of oak, have long been used as holding vessels in which wine is aged. Aging in oak typically imparts desirable vanilla, butter, and spice flavors to the wine. The size of the barrel plays a large role in determining the effects of oak on the wine by dictating the ratio of surface area to volume of wine with smaller holding vessels having a larger impact. The most common barrels are the Bordeaux barriques style, which hold 59 gallons (225 liters) followed by the Burgundy style barrel, which hold 60 gallons (228 liters). Some New World winemakers use the large hogshead 79-gallon (300 liters) size. Oak trees are typical between 80-120 years old prior to harvesting with the ideal conditions being a cool climate in a dense forest region that gives the trees opportunity to mature slowly and develop a tighter grain. The trees are typically harvested in the winter months when there is less sap in the trunk.
New barrels impart more flavors than do previously used barrels. Over time many of the oak properties get “leached” out of the barrel with layers of natural deposits left from the wine building up in the wood to where after 3 to 5 vintages there may be little or no oak flavors imparted on the wine. The cost of barrels varies due to the supply and demand market economy and can change with different features that a cooperage may offer. Generally these range from $500 to $1000 for a 59-gallon barrel that is made of approximately 33 staves put together. There is a need to optimize the quantity of wood used in aging alcoholic beverages; if thin layers of wood are used, it is likely that in each cycle, almost all of the extractable are removed from the wood, allowing the wood to be discarded after one or perhaps two uses. This approach will allow a consistent production of lots since any carry over effect due to partial depletion of the flavors from the wood will not contribute to variability.
Throughout history other wood types, including chestnut, pine, redwood, and acacia, have been used in crafting winemaking holding vessels. However none of these wood types possess the compatibility with wine that oak has demonstrated in combining its water tight, yet slightly porous, storage capabilities with the unique flavor and texture characteristic that it can impart to the wine that it is in contact with. Chestnut is very high in tannins and is too porous as a storage barrel and must be coated with paraffin to prevent excessive wine loss through evaporation. Redwood is too rigid to bend into the smaller barrel shapes and imparts an unpleasant flavor. Acacia imparts a yellow tint to the wine. Other hardwoods like apple and cherry wood have an off-putting smell. Austrian winemakers have a history of using Acacia barrels. Historically, chestnut was used by Beaujolais, Italian and Portuguese winemakers. Some Rhone wine makers still use paraffin coated chestnut barrels, but the coating minimizes any effect from the wood making its function similar to a neutral concrete holding vessel. In Chile, there are traditions for using a barrel made of rauli wood but it is beginning to fall out of favor due to the musky scent it imparts on the wine. Despite the use of a variety of woods, it has not been possible to combine several woods to create custom taste and palate. The current method of aging alcoholic beverages cannot control the loss of moisture predictably as it depends on various factors such as the type of wood, how it is coated, how it is bound together to form a barrel and several other factors leading to highly variable product that can often not be replicated. There is a need to develop an apparatus that will control the evaporation of alcoholic beverage during aging to allow the most optimal composition at the end of aging period.
While many attempts have been made in the past to accelerate the aging of the alcoholic beverages, there remains an unmet need to invent an apparatus that would allow aging to proceed extremely fast without modifying the natural process of aging that imparts unique character to the alcoholic beverages. This means several special features including allowing partitioning of components of wood through direct contact with wine through a surface as it is achieved during storage in barrels; the process must be gentle, yet expedited to reduce the time required for equivalent aging of the alcoholic beverages. The advantages of the instant invention are the reduction of the cost of the alcoholic beverages and improvement their organoleptic properties. A significant cost saving is accrued by aging larger volumes of alcoholic beverages in a single vessel; it is likely that the aging can be done with 100,000 L vessels instead of using 500 barrels. Such large volume handling is critical to successful commercial operations.
The instant invention involves introducing several wooden shelves in a large non-wood container; the flat surface of wooden shelves allows the calculation of the total surface area exposed and thus project the speed of aging. As the contact surface between the wood surface and the alcoholic beverage is increased several-folds and thereby the rate of natural transfer of chemical components of the wood to the alcoholic beverage is enhanced. The wooden shelves can be wafer-thin and their rigidity supported by a solid support such as a metallic or plastic surface of contained inside a mesh; the thinner is the disc, the higher is the surface area of exposed wood per gram introduced in the aging apparatus.